A low-potassium diet may reduce the burden on the kidneys and keep potassium levels in check. There are many foods that are low in potassium including fruits, vegetables, and lean protein sources.
Potassium is a mineral found in a variety of foods, and it plays many important roles in the body, including keeping fluid levels balanced.
The kidneys help filter fluids and excess waste products from the blood. In doing so, they balance out blood potassium and electrolyte levels.
However, some health conditions may limit the kidneys from functioning properly. This could lead to high levels of potassium, which may cause complications.
This article looks at why and for whom monitoring dietary potassium is important. It also explores which foods to eat, which to avoid, and how to prepare foods so that they contain less of the mineral.
Why potassium levels matter
Potassium is a key electrolyte in the body that helps support the function of a person’s:
- kidneys
- nerves
- heart
- muscles
Blood potassium levels that are too high or low may lead to serious complications, such as heart disease or cardiac arrest.
Hyperkalemia occurs when a person’s blood potassium levels rise above the healthy range of 3.5 and 5.0 mmol/L. This may impair the muscles that control the heartbeat and breathing, and could lead to:
- muscle weakness
- digestive problems
- numbness or tingling
Hypokalemia is when blood potassium levels are too low. This may cause symptoms like:
- muscle cramps
- increased urination
- constipation
Potassium also interacts with sodium. Without enough potassium in the body, high sodium levels may lead to an increase in blood pressure.
Low potassium foods
Making dietary changes may help a person manage their potassium levels.
However, it is important to keep in mind that the nutrient is crucial for health. The goal is to choose foods that provide enough of the mineral without causing a problematic buildup.
Many potassium-restricted diets limit potassium to 2000-3000 milligrams (mg) each day. However, a doctor may recommend a different target based on an individual’s condition.
Serving sizes
Low-potassium foods contain about 200 mg or less of the mineral per serving.
Unless otherwise listed, the serving size of each food below is a 1/2 cup. Having a larger serving increases the potassium content of a meal.
Fruits
Low-potassium fruits include:
- apples (1 medium) or apple juice or sauce
- blueberries
- blackberries
- strawberries
- raspberries
- cherries
- grapes or grape juice
- cranberries or cranberry juice
- pineapple or pineapple juice
- mandarin oranges
- grapefruit (1/2 fruit)
- watermelon (1 cup)
- plum (1 whole)
- tangerine (1 whole)
- peaches (1 small)
Vegetables
Low-potassium vegetables include:
- green beans
- peas
- alfalfa sprouts
- green or red cabbage
- raw white mushrooms
- cucumber
- eggplant
- kale
- lettuce
- onions
- peppers
- parsley
- rhubarb
- radishes
- watercress
- zucchini
- asparagus (6 spears)
- celery (1 stalk)
- fresh corn (1/2 ear)
Protein sources
Beyond vegetable sources, other low-potassium sources of protein include:
- eggs (up to 3 large)
- canned tuna (3 oz., drained)
- some cheeses (1.5 oz.)
Carbohydrate sources
Low-potassium foods that are rich in carbohydrates include:
- white rice
- white bread
- white pasta
- corn products, such as polenta and cornmeal grits
Drinks and snacks
Some low-potassium options include:
- rice milk
- coffee (limit to 8 oz.)
- tea (limit to 16 oz.)
- sparkling water
- cakes and pies without chocolate or fruits high in potassium
- cookies without chocolate or nuts
Tracking potassium levels
Most people do not need to reduce their potassium levels.
In fact, people in the United States consume too little potassium in their diets. If a healthy person consumes too much, their kidneys typically excrete the excess through the urine.
That said, kidney impairment, such as chronic kidney disease, may cause hyperkalemia.
Other causes for high blood potassium levels may include:
- diabetes
- medications that prevent normal urinary excretion of potassium
- Addison’s disease
- adrenal insufficiency
- congestive heart failure
- liver disease
A person with any of these health issues should work with a healthcare professional to keep their potassium levels in check. A doctor may also recommend medication to help remove the mineral from the body, such as diuretics or potassium binders.
Foods to limit or avoid
High-potassium foods contain more than 200 mg of potassium per serving.
Unless a serving size is provided, the average serving for the foods below is 1/2 cup.
That said, simply reducing the serving size may make some of these foods acceptable.
Fruits
The following are fruits that are typically high in potassium:
- raw apricots (2 medium)
- dried apricots (5 halves)
- dates (5 whole)
- avocados (¼ whole)
- bananas (½ whole)
- cantaloupe
- honeydew melon
- grapefruit juice
- kiwi (1 medium)
- mango (1 medium)
- nectarine (1 medium)
- orange (1 medium) or orange juice
- papaya (½ fruit)
- pomegranate (1 whole) or pomegranate juice
- prunes or prune juice
- raisins
Vegetables
Here are vegetables with higher levels of potassium:
- butternut squash
- artichokes
- bamboo shoots
- beets
- cooked broccoli
- brussels sprouts
- raw carrots
- leafy greens, except kale
- kohlrabi
- okra
- parsnips
- potatoes
- pumpkin
- rutabagas
- cooked spinach
- tomatoes
Nuts, seeds, beans, and legumes
Some legumes, beans, and seeds also contain more potassium, including:
- baked beans
- black beans
- nuts and seeds (1 oz.)
- peanut butter (2 tbsp.)
- dried beans and peas
- lentils
Other foods to avoid
- bran products
- chocolate (1.5-2.0 oz.)
- granola
- milk, all types (1 cup)
- molasses (1 tbsp.)
- salt-free broth
- yogurt
People looking to limit their potassium levels may also need to avoid salt substitutes, which may contain higher levels of potassium.
Leaching potassium from food
Leaching is a technique to help draw some potassium from foods.
A person should contact a doctor about the best approach and how much to leach before trying it at home.
Leaching potassium
Leaching potassium from vegetables may look like this:
- Peel and rinse the vegetables under warm water.
- Cut the vegetables into pieces that are 1/8 inch thick.
- Soak them in warm water for at least 2 hours. Use 10 times as much water as there are vegetables.
- Rinse them under warm water again.
- Boil them, using 5 times as much water as there are vegetables.
For some, leaching may be too time-consuming.
An older study from 2008 found that simply boiling some potassium-rich foods, such as cubed potatoes, for 10 minutes can reduce their potassium contents by up to 50%.
For canned or potted fruits and vegetables, drain and rinse them to remove any excess minerals in the canning liquid.
Summary
Potassium is a key mineral that supports a variety of important functions.
A person with a health issue affecting their kidneys or adrenal system may need to prevent this mineral from building up and must closely monitor their potassium intake.
A doctor may recommend a low-potassium diet. It is important to work with them closely to monitor potassium levels and keep them in check.
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